/**
 * CodeStyler.java
 * 
 * Bill Lynch & Matt Tucker
 * CoolServlets.com, October 1999
 * 
 * Please visit CoolServlets.com for high quality, open source Java servlets. 
 *
 * Copyright (C) 1999  CoolServlets.com
 * 
 * Any errors or suggested improvements to this class can be reported
 * as instructed on Coolservlets.com. We hope you enjoy
 * this program... your comments will encourage further development!
 * 
 * This software is distributed under the terms of The BSD License.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * * Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 * Neither name of CoolServlets.com nor the names of its contributors may be
 * used to endorse or promote products derived from this software without
 * specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY COOLSERVLETS.COM AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL COOLSERVLETS.COM OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * @(#)CodeStyler.java	1.6 02/06/13
 */
package com.sun.swingset3.codeview;

import java.util.*;

/**
 * A class that syntax highlights Java code by turning it into html.
 * 
 * <p>
 * A <code>CodeStyler</code> object is created and then keeps state as lines are
 * passed in. Each line passed in as java text, is returned as syntax
 * highlighted html text. (note: this class was originally named CodeViewer)
 * 
 * <p>
 * Users of the class can set how the java code will be highlighted with setter
 * methods.
 * 
 * <p>
 * Only valid java lines should be passed in since the object maintains state
 * and may not handle illegal code gracefully.
 * 
 * <p>
 * The actual system is implemented as a series of filters that deal with
 * specific portions of the java code. The filters are as follows:
 * 
 * <pre>
 *  htmlFilter
 *     |__
 *        multiLineCommentFilter
 *           |___
 *                inlineCommentFilter
 *                   |___
 *                        stringFilter
 *                           |__
 *                               keywordFilter
 * </pre>
 * 
 * @author Bill Lynch, Matt Tucker, CoolServlets.com
 * @version 1.6 06/13/02
 */
public class CodeStyler {

	private final static Map<String, String> RESERVED_WORDS = new HashMap<String, String>(); // >=
																								// Java2
																								// only
																								// (also,
																								// not
																								// thread-safe)
	private boolean inMultiLineComment = false;
	private String commentStart = "</font><font size=4 color=\"#0000aa\"><i>";
	private String commentEnd = "</font></i><font size=4 color=black>";
	private String stringStart = "</font><font size=4 color=\"#00bb00\">";
	private String stringEnd = "</font><font size=4 color=black>";
	private String reservedWordStart = "<b>";
	private String reservedWordEnd = "</b>";

	static {
		loadHash();
	}

	public CodeStyler() {
	}

	public void setCommentStart(String commentStart) {
		this.commentStart = commentStart;
	}

	public void setCommentEnd(String commentEnd) {
		this.commentEnd = commentEnd;
	}

	public void setStringStart(String stringStart) {
		this.stringStart = stringStart;
	}

	public void setStringEnd(String stringEnd) {
		this.stringEnd = stringEnd;
	}

	public void setReservedWordStart(String reservedWordStart) {
		this.reservedWordStart = reservedWordStart;
	}

	public void setReservedWordEnd(String reservedWordEnd) {
		this.reservedWordEnd = reservedWordEnd;
	}

	public String getCommentStart() {
		return commentStart;
	}

	public String getCommentEnd() {
		return commentEnd;
	}

	public String getStringStart() {
		return stringStart;
	}

	public String getStringEnd() {
		return stringEnd;
	}

	public String getReservedWordStart() {
		return reservedWordStart;
	}

	public String getReservedWordEnd() {
		return reservedWordEnd;
	}

	/**
	 * Passes off each line to the first filter.
	 * 
	 * @param line
	 *            The line of Java code to be highlighted.
	 */
	public String syntaxHighlight(String line) {
		return htmlFilter(line);
	}

	/*
	 * Filter html tags into more benign text.
	 */
	private String htmlFilter(String line) {
		if (line == null || line.equals("")) {
			return "";
		}

		// replace ampersands with HTML escape sequence for ampersand;
		line = replace(line, "&", "&#38;");

		// replace the \\ with HTML escape sequences. fixes a problem when
		// backslashes preceed quotes.
		line = replace(line, "\\\\", "&#92;&#92;");

		// replace \" sequences with HTML escape sequences;
		line = replace(line, "" + (char) 92 + (char) 34, "&#92;&#34");

		// replace less-than signs which might be confused
		// by HTML as tag angle-brackets;
		line = replace(line, "<", "&#60;");
		// replace greater-than signs which might be confused
		// by HTML as tag angle-brackets;
		line = replace(line, ">", "&#62;");

		return multiLineCommentFilter(line);
	}

	/*
	 * Filter out multiLine comments. State is kept with a private boolean
	 * variable.
	 */
	private String multiLineCommentFilter(String line) {
		if (line == null || line.equals("")) {
			return "";
		}
		StringBuffer buf = new StringBuffer();
		int index;
		// First, check for the end of a multi-line comment.
		if (inMultiLineComment && (index = line.indexOf("*/")) > -1
				&& !isInsideString(line, index)) {
			inMultiLineComment = false;
			buf.append(line.substring(0, index));
			buf.append("*/").append(commentEnd);
			if (line.length() > index + 2) {
				buf.append(inlineCommentFilter(line.substring(index + 2)));
			}
			return buf.toString();
		}
		// If there was no end detected and we're currently in a multi-line
		// comment, we don't want to do anymore work, so return line.
		else if (inMultiLineComment) {
			return line;
		}
		// We're not currently in a comment, so check to see if the start
		// of a multi-line comment is in this line.
		else if ((index = line.indexOf("/*")) > -1
				&& !isInsideString(line, index)) {
			inMultiLineComment = true;
			// Return result of other filters + everything after the start
			// of the multiline comment. We need to pass the through the
			// to the multiLineComment filter again in case the comment ends
			// on the same line.
			buf.append(inlineCommentFilter(line.substring(0, index)));
			buf.append(commentStart).append("/*");
			buf.append(multiLineCommentFilter(line.substring(index + 2)));
			return buf.toString();
		}
		// Otherwise, no useful multi-line comment information was found so
		// pass the line down to the next filter for processesing.
		else {
			return inlineCommentFilter(line);
		}
	}

	/*
	 * Filter inline comments from a line and formats them properly.
	 */
	private String inlineCommentFilter(String line) {
		if (line == null || line.equals("")) {
			return "";
		}
		StringBuffer buf = new StringBuffer();
		int index;
		if ((index = line.indexOf("//")) > -1 && !isInsideString(line, index)) {
			buf.append(stringFilter(line.substring(0, index)));
			buf.append(commentStart);
			buf.append(line.substring(index));
			buf.append(commentEnd);
		} else {
			buf.append(stringFilter(line));
		}
		return buf.toString();
	}

	/*
	 * Filters strings from a line of text and formats them properly.
	 */
	private String stringFilter(String line) {
		if (line == null || line.equals("")) {
			return "";
		}
		StringBuffer buf = new StringBuffer();
		if (!line.contains("\"")) {
			return keywordFilter(line);
		}
		int start = 0;
		int startStringIndex = -1;
		int endStringIndex;
		int tempIndex;
		// Keep moving through String characters until we want to stop...
		while ((tempIndex = line.indexOf("\"")) > -1) {
			// We found the beginning of a string
			if (startStringIndex == -1) {
				startStringIndex = 0;
				buf.append(stringFilter(line.substring(start, tempIndex)));
				buf.append(stringStart).append("\"");
				line = line.substring(tempIndex + 1);
			}
			// Must be at the end
			else {
				startStringIndex = -1;
				endStringIndex = tempIndex;
				buf.append(line.substring(0, endStringIndex + 1));
				buf.append(stringEnd);
				line = line.substring(endStringIndex + 1);
			}
		}

		buf.append(keywordFilter(line));

		return buf.toString();
	}

	/*
	 * Filters keywords from a line of text and formats them properly.
	 */
	private String keywordFilter(String line) {
		if (line == null || line.equals("")) {
			return "";
		}
		StringBuffer buf = new StringBuffer();
		Map<String, String> usedReservedWords = new HashMap<String, String>(); // >=
																				// Java2
																				// only
																				// (not
																				// thread-safe)
		// Hashtable usedReservedWords = new Hashtable(); // < Java2
		// (thread-safe)
		int i = 0;
		char ch;
		StringBuffer temp = new StringBuffer();
		while (i < line.length()) {
			temp.setLength(0);
			ch = line.charAt(i);
			// 65-90, uppercase letters
			// 97-122, lowercase letters
			while (i < line.length()
					&& ((ch >= 65 && ch <= 90) || (ch >= 97 && ch <= 122))) {
				temp.append(ch);
				i++;
				if (i < line.length()) {
					ch = line.charAt(i);
				}
			}
			String tempString = temp.toString();
			if (RESERVED_WORDS.containsKey(tempString)
					&& !usedReservedWords.containsKey(tempString)) {
				usedReservedWords.put(tempString, tempString);
				line = replace(line, tempString, (reservedWordStart
						+ tempString + reservedWordEnd));
				i += (reservedWordStart.length() + reservedWordEnd.length());
			} else {
				i++;
			}
		}
		buf.append(line);
		return buf.toString();
	}

	/*
	 * All important replace method. Replaces all occurences of oldString in
	 * line with newString.
	 */
	private static String replace(String line, String oldString,
			String newString) {
		int i = 0;
		while ((i = line.indexOf(oldString, i)) >= 0) {
			line = (new StringBuffer().append(line.substring(0, i)).append(
					newString).append(line.substring(i + oldString.length())))
					.toString();
			i += newString.length();
		}
		return line;
	}

	/*
	 * Checks to see if some position in a line is between String start and
	 * ending characters. Not yet used in code or fully working :)
	 */
	private static boolean isInsideString(String line, int position) {
		if (!line.contains("\"")) {
			return false;
		}
		int index;
		String left = line.substring(0, position);
		String right = line.substring(position);
		int leftCount = 0;
		int rightCount = 0;
		while ((index = left.indexOf("\"")) > -1) {
			leftCount++;
			left = left.substring(index + 1);
		}
		while ((index = right.indexOf("\"")) > -1) {
			rightCount++;
			right = right.substring(index + 1);
		}
		return rightCount % 2 != 0 && leftCount % 2 != 0;
	}

	/*
	 * Load Hashtable (or HashMap) with Java reserved words.
	 */
	private static void loadHash() {
		RESERVED_WORDS.put("abstract", "abstract");
		RESERVED_WORDS.put("do", "do");
		RESERVED_WORDS.put("inner", "inner");
		RESERVED_WORDS.put("public", "public");
		RESERVED_WORDS.put("var", "var");
		RESERVED_WORDS.put("boolean", "boolean");
		RESERVED_WORDS.put("continue", "continue");
		RESERVED_WORDS.put("int", "int");
		RESERVED_WORDS.put("return", "return");
		RESERVED_WORDS.put("void", "void");
		RESERVED_WORDS.put("break", "break");
		RESERVED_WORDS.put("else", "else");
		RESERVED_WORDS.put("interface", "interface");
		RESERVED_WORDS.put("short", "short");
		RESERVED_WORDS.put("volatile", "volatile");
		RESERVED_WORDS.put("byvalue", "byvalue");
		RESERVED_WORDS.put("extends", "extends");
		RESERVED_WORDS.put("long", "long");
		RESERVED_WORDS.put("static", "static");
		RESERVED_WORDS.put("while", "while");
		RESERVED_WORDS.put("case", "case");
		RESERVED_WORDS.put("final", "final");
		RESERVED_WORDS.put("naive", "naive");
		RESERVED_WORDS.put("super", "super");
		RESERVED_WORDS.put("transient", "transient");
		RESERVED_WORDS.put("cast", "cast");
		RESERVED_WORDS.put("float", "float");
		RESERVED_WORDS.put("new", "new");
		RESERVED_WORDS.put("rest", "rest");
		RESERVED_WORDS.put("catch", "catch");
		RESERVED_WORDS.put("for", "for");
		RESERVED_WORDS.put("null", "null");
		RESERVED_WORDS.put("synchronized", "synchronized");
		RESERVED_WORDS.put("char", "char");
		RESERVED_WORDS.put("finally", "finally");
		RESERVED_WORDS.put("operator", "operator");
		RESERVED_WORDS.put("this", "this");
		RESERVED_WORDS.put("class", "class");
		RESERVED_WORDS.put("generic", "generic");
		RESERVED_WORDS.put("outer", "outer");
		RESERVED_WORDS.put("switch", "switch");
		RESERVED_WORDS.put("const", "const");
		RESERVED_WORDS.put("goto", "goto");
		RESERVED_WORDS.put("package", "package");
		RESERVED_WORDS.put("throw", "throw");
		RESERVED_WORDS.put("double", "double");
		RESERVED_WORDS.put("if", "if");
		RESERVED_WORDS.put("private", "private");
		RESERVED_WORDS.put("true", "true");
		RESERVED_WORDS.put("default", "default");
		RESERVED_WORDS.put("import", "import");
		RESERVED_WORDS.put("protected", "protected");
		RESERVED_WORDS.put("try", "try");
	}
}
